Inhibitory Effects of Growth Differentiation Factor 11 on Phenotypic Transition Associated with Autophagy Deficiency in Mouse Coronary Arterial Myocytes

Abstract

Growth‐differentiation factor 11 (GDF11) as an anti‐aging factor may reverse age‐related cardiac hypertrophy in mice and cause youthful regeneration of cardiomyocytes. The role of GDF11 in the growth and phenotypic transition of vascular smooth muscle cells remains poorly understood. The present study first examined the effects of GDF11 to induce differentiation of cultured mouse coronary arterial myocytes (CAMs). By real time RT‐PCR and Western blot analysis, GDF11 was found to increase CAMs differentiation, as shown by increased expression of various muscle cell differentiation markers such as α‐SMA, myogenin, MyoD, and MyHC, but decreased expression of dedifferentiation markers such as vimentin and proliferating cell nuclear antigen (PCNA). Upregulation of GDF11 gene by trichostatin A (TSA) or specific CRISPR‐cas9 activating plasmids also stimulated the differentiation of CAMs with a remarkable decrease in the ratio of vimentin vs. SM22α. In CAMs treated with 7‐ketocholesterol (7‐keto), a phonotypic transition into dedifferentiation status was observed with significant increases in the ratio of vimentin vs SM22α, which was companied by autophagosome (AP) accumulation with large increase in LC3‐II. This 7‐keto‐induced CAMs dedifferentiation and AP accumulation were almost completely blocked by GDF11 or TSA treatment. Similarly, in CAMs pretreated with lysosome function inhibitor, bafilomycin or chloroquine, both GDF11 and TSA markedly attenuated the phenotypic transition and AP accumulation. Moreover, in CAMs from mice lacking CD38 gene that produces lysosome trafficking regulator, NAADP, GDF11 was also shown to inhibit phenotype transition to dedifferentiation status with or without 7‐keto pretreatment. It is concluded that both exogenous and endogenous GDF11 promote CAMs differentiation and prevent a phenotypic transition of these cells by reduction of lysosome accumulation induced by different pathological stimuli.Support or Funding InformationSupported by NIH grants HL057244, HL075316 and HL122937